1. How do i get the album cover back in the lower left corner?
2. How do I get the old "full" search function back? I really liked the way it searched in the previous version - the new drop-down feels cramped.

1. You can get the side bar back by going "view > Show Sidebar" Although I haven't found a way to get the square back in the bottom corner that shows the current playing track.

2. When you are typing a search, the top field in the drop down says Show "{whatever}" in Music. If you select this it will show in the main window the search results based on whatever tab you are in (Songs/Album/Artist/...)

Regarding #2: In the search bar there is a little arrow next to the magnifying glass, click on it. Once the pull-down menu is visible, ensure that Search Entire Library is unchecked and Filter by All is checked.